We fiction readers have an almost universal weakness for books about People Like Us. Given a choice between a novel about a bunch of foreigners in China, say, and one about two middle-class English families on holiday in Wales, the average British book-buyer will plump for the story closer to home. It’s less of an effort. But there’s a price to pay for seeking the familiar. Finish the book and nothing’s changed.

Mark Haddon’s The Red House appeals for just this sense of comfortable kinship. Extending one’s imagination to embrace these characters isn’t a strain: Richard, an emotionally repressed hospital consultant with a legal suit looming over his head; his new wife, Louisa, who works for a digital scanning company and is cowed by her husband’s status as a doctor; Louisa’s vain, catty 16-year-old daughter, Melissa, who’s been bullying another girl at school by circulating a sexually compromising photograph; Richard’s sister Angela, a teacher still anguishing over a stillborn child whose apocryphal 18th birthday approaches; Angela’s husband, Dominic, long unemployed and latterly working part-time in Waterstones, compensating for his bruised masculinity by having an affair with a needy younger woman.

Then there are Angela and Dominic’s three children: Alex, a healthily priapic 17-year-old running enthusiast; Daisy, who at 16 has latched on to an Alpha Course Christian identity, to her secular family’s dismay; Benjy, a boisterous eight-year-old, who lives in his own world the way children are supposed to and isn’t – in contrast to the protagonist of Haddon’s Whitbread-winner The Curious Incident of the Dog in the Night-Time – autistic.

The set-up is accessible as well, since many an extended family has experienced the claustrophobia and volatility of being shut up in a cottage with nothing on the agenda but – the horror, the horror – fun. Estranged from his sister for 15 years and following the death of their mother, Richard has invited Angela and her family to share a rental house on the Welsh border for a week. Isolation and fractious proximity produce a variety of revelations and self-discoveries.

The two grown siblings compare notes, to find their versions of both parents don’t remotely square; they compete over who’s more resentful – Richard, for having shouldered their mother’s alcoholism as a boy, or Angela, for having shouldered their mother’s geriatric deterioration in adulthood. Daisy struggles with a growing realisation she’s a lesbian; Melissa struggles with a growing realisation she’s a bitch. Angela works herself into a crisis of grief over her lost child; Dominic works himself into a crisis of conscience over his affair.

Haddon is a gifted writer and lifts the tone above soap opera. Nevertheless, there is a soporific mildness to this book – to the characters, the plot, and even the writing. I didn’t mind it – the experience of reading the novel was pleasant enough – but in short order I’m certain to forget all about it (alas, like most books).

Perhaps the project’s inherently humble scale encouraged a handful of self-consciously literary stylistic choices that some will see as perfectly agreeable and others will perceive as affected. The fact that point of view ricochets between all eight characters, often switching two or three times in a page, may lend the novel a disjointedness but also generates a sense of energy and motion without which, given the plot’s modesty, the book might sag. Intermittent blocks of text, comprising lists of nouns, add a poetic touch (“The Black Mountains a smoky blue in the day’s haze. Rhydspence. A moss-greened hull upended against a tiny shed. The five arches of the toll bridge at Whitney-on-Wye”), though the device is overdone and impatient readers will start to skip them. But the ghostly appearances of Karen, the stillborn baby, are likely to seem sentimental and gratuitous to just about everybody.

Two technical aspects of the text grate for me but these may seem eccentric bugbears, so feel free to dismiss them as my little problems. First, the refusal to employ the unreal conditional throughout (italics added): “as if it was a mystery object”; “as if she was a colleague”; “as if he was wearing ...” And then suddenly on page 133 we read “as if she were stepping away”, and we’re left to wonder who’s the grammatical wally: the author or the copy editor? Second, all dialogue is in italics. I yearn for a single literary writer to rediscover the quotation mark, in all its unpretentious glory.

To do Haddon justice, the odd passage really does rise above: “And now you must do nothing for a week and enjoy it. Days of rest long past the point when we’re rested, holidays without the holy, pilgrimage become mere travel, the destination handed to us on a plate, the idleness of the empire in its final days.” Yet in the main this novel fails to meet its flap copy’s promise to explore “the extraordinariness of the ordinary” and instead merely explores the ordinariness of the ordinary. There’s only so much of a frisson of recognition to be garnered from reading about another oral hygiene obsessive who uses the interdental tip on his electric toothbrush. Maybe next time we should push ourselves and read that novel about China.